基于FPGA的自由空间音频信号传输及频谱显示系统

自由空间光通信技术随着设备成本的下降，相关应用也在不断扩展。基于自由空间光通信技术，我们搭建了一个音频信号传输系统。以声音信号调制的激光作为信号源，采用光电晶体管及其反馈电路对信号进行接收，并使用FPGA组成的控制电路实现信号解调，还原初始信号。同时实现了FIR滤波，FFT变换和VGA时序。我们完成了系统搭建和测试，实现了高识别率、低成本的自由空间音频信号传输及频谱显示。

Free Space Transmission of Audio Signals and Spectrum Display System Based on FPGA

With the decline in the cost of equipment of free space optical communication technology, related applications are also expanding. We built an audio signal transmission system based on free-space optical communications technology. One laser beam is modulated by a voice signal, and then transmited in the air. It is demodulated on a receiver consisting of a phototransistor, a feedback circuit and a control model. The original audio signal is finally obtained by a control circuit composed of FPGA for demodulation. The system achieves FIR filtering, FFT transform and VGA timing. We have completed the system and the experimental results show that a high recognition rate, low-cost free-space audio signal transmission and spectrum display system is realized.